Processing induced nanoscale heterogeneity impact on the mechanical and electrical behavior of Cu–Zr thin film metallic glasses

The variation of structural heterogeneity at the nanoscale can significantly impact the mechanical and electrical properties of thin film metallic glasses (TFMGs). Such nanoscale heterogeneity is closely related to the diverse atomic configurations in the amorphous structure, which are influenced by TFMGs processing history. In this study, we investigate the impact of processing-induced local nanoscale heterogeneity of TFMGs on the mechanical and electrical properties by tuning the sputtering targets, e.g., single CuZr target vs. co-sputtering of Cu and Zr target to tune the nanoscale heterogeneity. Specifically, Cu50Zr50 TFMGs are synthesized by sputtering a single CuZr target (single-CuZr) and co-sputtering Cu and Zr target (co-CuZr), respectively. The varying nanoscale heterogeneity was determined via a dynamic atomic force microscopy measurement. The single-CuZr, possessing nanoscale heterogeneity with ∼25.9% less correlation length, are found to have ∼28.5% higher modulus, and ∼6.1% higher hardness than those of co-CuZr TFMGs. Under the heat treatment at the same temperature (573 K), the difference in nanoscale heterogeneity makes the two films exhibit opposite manner, with the relaxation of single-CuZr and rejuvenation of co-CuZr, leading to a variation in the electrical and mechanical behaviors of TFMGs. Our work implies the significance of the processing-dependent structural heterogeneity at the nanoscale of TFMGs, which could be used to tailor the TFMGs for multifunctional applications